COP30 – from laudable aims to practical action?

Every year, world leaders gather to find ways of limiting global warming. The latest of these ‘COP’ meetings, COP30, is in Belém, Brazil from 10 to 20 November 2025. COP stands for ‘Conference of the Parties’, the decision-making body of the United Nations Framework Convention on Climate Change (UNFCCC).

Perhaps the best-known of these meetings was in Paris in 2015. This resulted in the Paris Agreement. This is a legally-binding international treaty to limit global warming to well below 2°C and preferably to 1.5°C above pre-industrial levels. This would involve reducing greenhouse gas emissions and/or taking carbon absorbing measures. All UN countries except for Iran, Libya and Yemen are signatories to the agreement.

However, on coming to office in January 2025, President Trump announced that the USA will withdraw from the agreement in January 2026. Instead, he would prioritise fossil fuel production, under the mantra, ‘drill, baby, drill’. Previously he had claimed that global warming is a hoax concocted by China designed to undermine the competitive power of the USA.

Progress in reducing emissions and mitigating climate change

Since 2020, each country has been required to submit its own emissions-reduction targets, known as ‘nationally determined contributions’ (NDCs), and the actions it will take to meet them. Every five years each country must submit a new NDC more ambitious than the last. New NDCs are due this year. As of 12 November, 112 of the 197 countries had submitted a new NDC (including the USA, China, the EU and the UK). These 112 countries account for around 71 per cent of global emissions.

Implementing all new NDCs would reduce global CO₂ emissions by between 15 and 25 per cent from current levels by 2035. But this would merely reduce global warming to around 2.6°C above pre-industrial levels. Approximately 35 per cent emissions reductions by 2035 would be required to restrict global warming to 2°C and 55 per cent to restrict it to 1.5°C.

But implementing the Paris Agreement has still had a high degree of success. Without the action taken and being taken over the past 10 years, it is predicted that global temperatures by 2050 would rise by 3–3.5°C.

Rich countries are expected to provide finance to low-income countries. This is required to help such countries adopt green technologies and to adapt to the harmful effects of climate change (e.g. through irrigation schemes and flood defences). At COP29 in Azerbaijan, the ‘Baku Finance Goal’ was agreed. This is an agreement to provide climate finance of $1.3 trillion per year by 2035 to developing countries from all public and private sources.

The subsequent ‘Baku to Belém Roadmap’ provides a set of suggested actions for governments, financial institutions and the private sector to bridge the gap between current climate finance flows and the $1.3 trillion agreed to meet global climate goals. The roadmap is a central focus of the COP30 conference in Belém, with discussions between countries on how to translate the Baku finance goal into concrete, tangible actions and integrate it into formal decisions.

The role of Donald Trump

As well as announcing that the USA will withdraw from the Paris Agreement in January 2026, since coming to office in 2025, President Trump has given billions of dollars of tax cuts to fossil fuel firms and allowed drilling for oil and gas on federal lands. At the same time, he has described renewable energy as ‘a joke’ that will bankrupt countries and has slashed subsidies and tax breaks for solar and wind power, withdrawn permits for wind and solar farms, and cut funding for green energy research.

He wants the USA to be world leader in fossil fuel energy, calling on governments to buy US oil and gas, threatening some countries with tariffs if they do not. Already, Japan, South Korea and several European countries have agreed to buy huge quantities of US oil and liquefied natural gas (LNG). A worry is that other similarly inclined governments, such as Argentina, may roll back on their commitments to a green transition and instead boost their fossil fuel industries.

This gives added urgency to the Belém talks. It is crucial for the rest of the world to stick together in pushing ahead to combat global warming and in adopting and sticking to tough NDCs. It is also crucial for rich countries to support dlow-income countries in adopting climate-friendly investment and in measures to mitigate the effects of global warming.

The economics of climate change

Climate change is directly caused by market failures. One of the most important of these is that the atmosphere is a common resource: it is not privately owned; it is a global ‘commons’. Individuals and firms use it at a zero price. If the price of any good or service to the user is zero, there is no incentive to economise on its use. Thus for the emitter there are no private costs of using the atmosphere in this way as a ‘dump’ for their emissions and, in a free market, no incentive to reduce the climate costs.

And yet when firms emit greenhouse gases into the atmosphere there are costs to other people. To the extent that they contribute to global warming, part of these costs will be borne by the residents of that country; but a large part will be borne by inhabitants of other countries.

These climate costs are external costs to the firm and are illustrated in the figure. It shows an industry that emits CO₂. To keep the analysis simple, assume that it is a perfectly competitive industry with demand and supply given by curves D and S, which are equal to the marginal private benefits (MPB) and marginal private costs (MPC), respectively. There are no externalities on the demand side and hence MPB equals the marginal social cost (MSB). Market equilibrium is at point a, with output at Q_pc and price at P_pc. (Click here for a PowerPoint.)

Assume that the emissions create a marginal cost to society equal to MEC_c. Assume that the MEC increases as output and total emissions increase. The MEC_c line is thus upward sloping. At the market price of Q_pc, these external climate costs are equal to the purple vertical line. When these external climate costs are added to private costs, this gives a marginal social cost given by MSC = MPC + MEC_c. The gives a socially optimal level of output of the product of Q* at a price of P*, with the optimum point of c.

In other words, other things being equal, the free market overproduces products with climate externalities. If the output is to be reduced to the social optimum of Q*, then the government will need to take measures such as those advocated in the Paris Agreement. These could include imposing taxes on products, such as electricity generated by fossil fuels, or on the emissions themselves. Or green alternatives, such as wind power, could be subsidised.

Alternatively, regulations could be used to cap the production of products creating emissions, or caps on the emissions themselves could be imposed. Emissions permits could be issued or auctioned. Only firms in possession of the permits would be allowed to emit and the permits would cap emissions below free-market levels. These permits could be traded under a cap-and-trade scheme, such as the EU’s Emissions Trading Scheme. Again, such schemes are advocated under the Paris Agreement.

COP30 and progress in tackling climate change

The USA is not attending COP30 in Brazil. Nor is the Chinese leader, Xi Jinping. However, there are growing opportunities for translating aims into practical policies for specific sectors, such as energy, transport and carbon-intensive industries. These policies may require some degree of government action – taxes, subsidies or regulation – to internalise climate externalities. But increasingly, green alternatives are becoming economically viable without subsidies or with just initial government funding to ‘crowd in’ private investment, which will then attract further private capital as external economies of scale kick in. Increasingly investors will find profitable opportunities in climate-friendly projects.

At the same time, while the USA is moving away from climate-friendly investment (as least for the term of the Trump Presidency), China is moving in the opposite direction, with massive investment in solar panels, wind turbines, EVs and batteries – investment that is bringing down their cost and thereby encouraging their adoption around the world. Such technologies create huge opportunities for low-income countries to provide affordable energy and to create local jobs, both skilled and unskilled. It also helps them achieve much greater energy security by reducing their reliance on fossil fuel imports

Chinese advances in green technology are also providing a stimulus to other countries to invest in renewable industries to prevent Chinese dominance. The danger, however, of Chinese dominance in the renewable sector in high-income countries is that it may encourage them to impose tariffs on Chinese imports of EVs, solar panels, etc. to protect their own industries.

But despite the growing opportunities for profitable adoption of green technologies without government support, there is still much that governments need to do to encourage the process. COP meetings are an important forum for discussing such policies and holding governments to account for meeting or not meeting their targets.

Articles

• What is COP30 and why does it matter for the climate?

Chatham House, Anna Åberg (5/9/25)

• COP30 in Brazil: What is at stake for global collaboration on climate and nature?

World Economic Forum, Pim Valdre (5/11/25)

• What is COP30 and why does it matter?

CNN, Laura Paddison (11/11/25)

• Why COP 30 in Brazil Matters for a Thriving Economy and a Safe, Livable Planet

Union of Concerned Scientists (UCS),Rachel Cleetus (7/11/25)

• Nationally Determined Contributions: The Action Plans Behind Global Efforts To Fight the Climate Crisis

Center for American Progress (CAP, Kalina Gibson and Courtney Federico (22/9/25)

• New climate pledges only slightly lower dangerous global warming projections

UN Environment Programme, Press Release (4/11/25)

• COP30: Trump and many leaders are skipping it, so does the summit still have a point?

BBC News, Justin Rowlatt (10/11/25)

• Trump dismisses clean energy as ‘a joke.’ But Americans deserve facts, not fear

USA Today, Mark McNees (23/9/25)

• The surprising countries pulling off stunningly fast clean energy transitions

CNN, Ella Nilsen and Samuel Hart (7/11/25)

• COP 2025: Outlook and Implications for Investors

RankiaPro, Joanna Piwko, Allegra Ianiri, Marie Lassegnore and Jean-Philippe Desmartin (10/11/25)

Information and Data

• United Nations Framework Convention on Climate Change

United Nations Framework Convention on Climate Change (UNFCCC)

• UN Climate Change Conference – Belém, November 2025

United Nations Framework Convention on Climate Change (UNFCCC)

• Baku to Belém Roadmap to 1.3T

United Nations Framework Convention on Climate Change (UNFCCC)

• NDC Tracker

Climate Watch

Questions